The Verso blog has a piece on populism by Jacques Rancière that was originally published in 2011 but is arguably even more illuminating now, given the global resurgence of both right-wing and left-wing populism. Rancière contends that populist politics doesn't so much represent a people as construct it, in the service of, paradoxically, "concluding that we have to place ourselves in the hands of those who govern us, and that any challenge to its legitimacy and integrity is opening the door to totalitarianisms." Here's an excerpt from the piece:

But in today’s Europe the label "populism" is used to designate something else. It is not a mode of government. On the contrary, it is a certain attitude of refusal, faced with the reigning practices of government. What is a "populist," as today defined by our governmental elites and their ideologues? Beyond all the many variations on this word, the dominant discourse seems to characterise it by way of three essential traits: (1) a style of interlocution that addresses the people directly, going around its representatives and its notables; (2) the claim that governments and ruling elites are more concerned with their own interests than the res publica; (3) an identitarian rhetoric that expresses fear and rejection of foreigners.

Yet it is clear that there is no necessary link between these three characteristics. Our constitutions themselves assert the existence of an entity called the people, which is the source of power and the privileged interlocutor of political discourse. This was the same conviction that the republican and socialist orators of yesteryear elaborated, with no hidden agenda. This is not bound to any form of racist or xenophobic sentiment. It does not take any demagogy to assert the claim that our politicians think more about their careers than the future prospects of their fellow citizens and that our rulers live in symbiosis with the representatives of big financial interests. The same press that attacks the "populist" drift day after day offers us the most detailed proof of this. For their part, heads of state and government sometimes accused of populism, like Berlusconi or Sarkozy, steer well clear of propagating the "populist" idea that the elites are corrupt.

The term "populism" does not serve to characterise a definite political force. On the contrary, it draws its strength from the amalgams it allows to be made between political forces stretching from far Right to radical Left. Nor does this term designate an ideology or even a coherent political style. It simply serves to paint a picture of a certain people.

For "the people" does not exist. What do exist are different — sometimes antagonistic — figures of the people, constructed figures that privilege certain ways of assembly, certain distinctive traits, certain capacities or incapacities: an ethnic people defined by the community of blood or land; the people-flock watched over by good shepherds; the democratic people that sets in motion the competency of those who have no particular competency; the ignorant people that the oligarchs keep at bay; etc. The notion of populism itself constructs a people characterised by the fearsome alliance of a capacity — the brute power of the majority — and an incapacity — the ignorance attributed to this same majority.